An electronic component mounting system for mounting electronic components on a substrate to produce a mount substrate includes a plurality of connected devices for electronic components mounting such as a solder printing device, an electronic components installation device, and a reflow device. In recent years, upon requests to improve mounting operation accuracy and requests to improve productivity, systems for feedforwarding inspection results in individual steps of the electronic components mounting devices to a downstream process have been used (e.g., see Patent Document 1). In the related art shown in this patent document example, in components mounting in which electronic components are mounted on a multiple substrate that includes a plurality of unit substrates, whether a printed state of solder is good or bad is judged by a solder printed state inspection, and a result of the judgment is fed forward as solder inspection data to an electronic components installation device in a downstream process. Thus, the effect of capable of eliminating a waste of mounting the electronic components on the unit substrates that have printing failures is achieved.